A power source device with a plurality of battery cells is used, for example, in automotive applications as the power source in a vehicle such as a hybrid vehicle or electric vehicle. This type of power source device is made up of battery blocks having a plurality of stacked battery cells. Further, an electric circuit board is positioned on the upper surface of the battery blocks. This circuit board has a monitoring circuit which monitors a temperature, a voltage, or the like, and detects whether or not abnormalities happen. One example of such power source device is shown in a perspective view of FIG. 10 (Patent Literature 1). In a power source device 800 shown in this figure, a circuit board 826 is fixed by screws on the upper surface of stacked structure of prismatic battery cells 801. In addition, each of the battery cells 801 is connected to a temperature sensor or a voltage sensor. The circuit board 826 is connected to harnesses extended from the temperature sensor and the voltage sensor connected to each of the battery cells 801.
According to the demands on the enhancement of capacity, as the number of secondary battery cells increase, the number of harnesses extended from the temperature sensor and the voltage sensor connected to the battery cells are increasing. On the other hand, as there are the demands on downsizing the power source device, it is difficult to increase in the size of the circuit board.
In the harnesses extended from such sensors and connected to the circuit board, in order to enhance noise immunity, shortening the length of the harnesses is required. Accordingly, the harnesses are connected to the side of the circuit board. However, under circumstances of both increasing the number of the sensors and not permitting increasing in the size of the circuit board, as shown in a plan view of FIG. 11, the connectors have to be disposed side by side. In the example of this figure, a first connector 965 is disposed at the side of a circuit board 926, and a second connector 966 is disposed at the inside of the first connector 965.
In such disposition, a first harness extended from the first connector 965 can be connected by the conventional example, but a second harness 964 extended from the second connector 966 disposed at the inside of the first connector 965 is extended to the outside beyond the upper surface of the first connector 965 as shown in a side view of FIG. 12. In this structure, the second harness 964 extended from the second connector 966 interferes with the connector 965 at the side.
In order to avoid this interfering, when the second harness 964 is extended from the first connector 965 upward, a space which stores the second harness 964 is necessary at the upper portion from the first connector 965. Then, as the space in the direction of the height in the circuit board is necessary, as a result, the height of the power source device can be big. In addition to the direction of the height, in the horizontal direction, as shown in FIG. 11 and FIG. 12, in order that the second harness 964 is extended, it is necessary that the second connector 966 is disposed in spaced relationship with the first connector 965. Namely, it is difficult that the second connector 966 and the first connector 965 are not adjacently disposed. As a result, a large area in the circuit board where the connectors or the harnesses are disposed is necessary, and then it increases in the size of the power source device. Especially, in the resent trend of downsizing the power source device including its height, when such enlargement or increasing in the height is not permitted, there is a trouble in disposing the harnesses.